Draft gear



June 13, 1933. E, H, scHMlD-r Er AL 1,913,414

l DRAFT GEAR Filed Nov. l5, 1928. 2 sheets-'sheet 1 F .j E! 1817 /W 20/ zr l \w\\ \l k\\\\\ z f l f V T fg f mnmm n June 13, 1933. E. H. SCHMIDT Er AL 1,913,414

DRAFT GEAR Filed Nov. 13, 1928 2 Sheets-Sheet 2 vwmtozy Einestj. Schmidt Fabertldpence lumai CLM/576,1,

` UNITEDSTATES Patented .lune 1 3, 1933 PATENT OFFICE f y ERNEST HusoHMInT, `or CLEVELAND HEIGETsY-IAN) HUBERT L. srENoE, or EAST r t cLEvELaEn, onto, -AssreNoRs To NATIONAL MALLEABLE AND STEEL CASTINGS COMPANY, or CLEVELAND, oH1o,A coRroRATIoN or oHro i. i

DRAFT GEAR Application med Nvembr 1a, 192s, serial No. 319,064.

Our invention relates to improvements in draft gears and is `directedto `providing a draft gear with a much greater spring`ca pac-ity than has hitherto been usedand in providing means for frictionally retarding j the recoil action of the springs. i

Inmodern friction draft gears thefric` `tional resistance provides a far greater proi portion of theshocl; absorbing or cushioning power ofthe gear than does the spring' caj pacity. As a result the gear action `is not as smooth as isdesired, for the reason that the frictional resistance `developed by rubbing metal on metal under heavy pressures, which is greatly in eXcessof the spring resistance, is apt to cause a series of perceptible jolt-sand jarswhich it is desirable to eliminate. For

the purpose of overcoming the rough riding action of such gears We have provided a draft gear with sufficiently highspring capacity to take care of all steady running loads, to which we have addedfrictional capacity, which, to-

gether with the spring capacity, is adequate to resist impact shocks. Our improved gear on release also develops suiicient friction to retard or snub the recoil of the' high capacity springs to a point which will assure smooth riding. Our `invention also comprises various features which we shall hereinafter describe and claim. 'A A1 f In the accompanying drawings, Fig'. 1 is a top plan View, partly in section, of a draft gear embodying our invention; Fig. 2 is a side elevation partly in section; Fig.` 3 is a r section on lines IIIe-III of Fig. 1; Fig. 4 is an elevation of the inner surface of the wedge;

and Figs. 5 and 6 are diagrammatichviews of modifiend forms of our invention.

Referring more particularly to the drawings, the gear has a case 2, preferably rectan gular in form, in opposite sides 3 of which are seated the friction members 4, each of which ispreferably a rectangularl block having at its inner end a lateral projection 5.`

In each side wall 3` is a recess `6 for the projection 5, `which preferably has rsuiicient clearance to permit a limited movement'of the frictional member 4 longitudinally as well as laterally of the case.

To resist the inward( `thrust of the frictional members 4, the case here-illustrated. The inclined forward faces 10 of thfe'shoes 9are engagedlby correspond ingly inclined faces 11 of the wedge 12.

`Each shoeface 10 has also aninclined recess 13`into which fits a correspondingly inclined rib or flange 14 onto the wedge 12 for the purpose of maintaining the shoes and wedge ing faces in alignment and of preventing the shoes 9 from working laterally over to and abrading the sides of the case 2.

The' wedge12 has a central projection 1 which forms a bearing for the forward end of the central spring 16V and also serves to hold the friction members from working inwardly from the seat against the inner surface of the case 2. The forward `ends of the side springs 17, of which we have shown two foreach pair of shoes, bear against the spring follower 18, andeach spring follower bears against the vertically disposed rear faces19 of the projections 20 on a pair of the shoes 9. The backs of the shoes are` also recessed at21, and the friction members at 22,`to provide clearance, respectively, for the sidesprings 17 andthe central spring 16. The wedge 12 is heavily braced acrossits central portion by the ribs 23, which` tie together `the opposing wedge faces to resist the heavy-bursting stresses to which `the wedge'is subjected.`

When understrong compression, the wedge 12 drives the shoes `9 `rearwardly against the pressure ofthe springs 17 and the wedge `it self directlyagainst the pressure of the spring 16. At the same time a certainamount of friction is` developed betweentheVsides of the friction members 4 and the faces of the friction shoes "9 in contact with such sides, theamount of such friction being dependent on the angle of inclination of the sides of the friction members to the longitudinal axis of the gear. The parts of the gear are proportioned so that just before the springs go solid the wedge will come into engagement with the end of the case and thereby protect the springs against oversolid blows.

As has been stated above, the projections 5 have a limited amount of clearance in their seats 6 in the case. This is for the purpose of permitting the members 4 to tip with the wedge 12 and shoes 9 in case an angular blow strikes the Wedge l2, without disturbing the frictional grip of the parts. rIfhis lateral clearance also allows the inembers4 to shift bodilylaterally to compensate for inequali-4 ties in the size of the shoes.` In release the frctonal engagement 0f the Shees against the frictional members retards or dampens the recoil of theA springs` and thus prevents sudden shock or ar to the car during the restoration ofthe parts to their original positions- In a gear of the type just described, in which the springs have a resistance under initial compression of about 21,000 pounds and a maximuml resistance of about 76,000 pounds, i. e., approximately equal to the maximum sustained drawbar pull of a modern locomotive, we have foundv that the frictional resistance developed during compression was upwards of (5,000pounds and was ample to take. care 0f impact blows and the Compression involved in sudden stops and starts.

ends-that is, the frictional members are madeto wielen toward their rear ends. As

is shown in F ig. 5, thedotted line a is parallel to the longitudinal center line of the gear and at an. anglefto the tapered face b 'of the friction member. Vllith the frictionalr mem- 1 bers 84tapered approximately four-tenthsof an inch in a foot, and a corresponding taper on the face olf-the shoes 39, we have found that the added frictional resistance of the gearwillbe upwards of 350,000 pounds, but

onk release the dampening or, absorbing ef,-

fectof the frictional elements upon the spring recoil will-be lessened.

If -it is desired to increaSQthe dampening o r. absorbingreffect, of the frictional elements,

tlusmay beeffeced. as sshownn Fig. 6,

by reversing the taper on the shoes 49 and frictional members 44; that is, the front ends of the friction member are wider than their rear ends. A tap-er of the order of fourtenths of an inch in a foot, with a corresponding taper on the shoes, is sufficient to augment considerably the dampening or absorb ing action of the frictional elements, but for purposes of illustration a somewhat greater taper is shown, the dotted lines c `being parallel to the longitudinal center line members 4 inthe sides of the case 2 and be- J tweenA the springs 17 together with the use of opposed, relatively short friction shoes arranged in. pairs, whichy allows the maximum amount of space to be reserved for springs without encroaching upon the standard dimensions allowed for draft gears.

It will thus be seen that gears embodying our invention are capable of being used to meet a wide range of service conditions from gery heavy freight to light passenger traf- The terms and expressions which we have employed are used as terms of description and1 not of limitation, and we have no intention, in the use of such terms and expressions,

ofexcluding any mechanical equivalents of the features shown and described, or portions thereof, but recognize that various structural modifications are possible within the scope of the invention claimed.

y What we claim is:

l. In ay draft gear, a case, friction members anchered within the case, a pair of friction shoes in frictional engagement with eachy member, spring elements, a spring follower inengagement witheach pair ofy shoes, a pair of said spring elements in engagement with each follower, and a wedge engaging all ofthe shoes,l one ofthe spring elements engaging the wedge.

2. Ina draft gear, ay case, a plurality of friction members anchored in the sides of the Case, a, plurality of pairs of friction shoes, each pair in frictional engagement with a corresponding one of-said members on opposite sides thereof, spring elements compressed by each pair of shoes, and a wedge engagingsaid shoes, the wedge and each shoe having a slotand projection engagement to guide the movement of the shoes.

llO

\ the shoes of each pair being in engagement with opposed sides of the corresponding `friction member, spring elements compressed by said shoes 4and a wedge engaged by said shoes, the members being positioned in the casing adjacent the frictional zone thereof and so constructed and arranged in said cas-- ing as to move with said shoes in a direction at an angle to the axisof the casing to oompensate for oifcentered blows without disturbing the frictional grip of the shoes on the members.

`1. In a draft gear, a case, at least one friction member extending longitudinally in the case, friction shoes in engagement with each such member and a wedge engaging the shoes, each such member being held substantially from longitudinal movement relative to the case but loosely secured thereto for bodily movement in a lateral direction relative to said case to compensate for offcentered blows without disturbing the frictional grip of the shoes on the member.

5. In a friction draft gear, a housing, a plurality` of friction members mounted in said housing, friction shoes arranged on opposite sides of said friction members a wedge pressing said shoes against said members, and spring means resisting the move- Iment of said shoes, said means beingarranfed on o osite sides of said friction members, and additional spring means between said members and resisting movement of said wedge.

shoe and resisting the movement thereof,

and a centrally located spring between said friction members and resisting movement of said wedge.

7. In a draft gear, a case, frictionmembers anchored within `the case and movable relatively to each other, a pair of friction shoes in frictional engagement with each member on opposed sides thereof, all of said shoes being so located in said case as to be cut by a common transverse plane, spring elements compressed by each pair of shoes, and a wedge engaging all of said shoes.

8. In a friction draft gear, a casing, a plurality of friction members anchored 1n the `side walls thereof and extending inwardly of said casing, friction shoes in engagement with opposite sides of each of said friction" members, a wedge engaging said shoes, and spring resistance means opposing movement of said wedge and arranged to prevent disengagement of said friction members from said sidewalls. n

` 9.` In a draftl gear, a case, friction members within the` case,a pair of friction shoes in frictional engagement `with each member on opposite sides thereof, spring elements compressed by said shoes, and a wedge engaged by said shoes, the members being loosely secured to the i casing adjacent the fric` tional Zone thereoffor free angular movement relative to said case to compensate` for olf-centered blows without disturbing the frictional grip of the shoes on the members.

10.- In a draft gear, a case, a friction member extendinglongitudinally inthe case, friction shoes in engagement with said member on opposite sides thereof and a wedge engaging the` shoes, said member being held substantially from longitudinal movement relative-to the case but loosely secured thereto for bodily movement in a lateral direction relative to said case to compensate for off-centered blows without .disturbing the frictional grip of the shoes on the member, and `spring means opposing longitudinal movement of said shoes with respect to said case. i.

11. `In a draft gear a case, friction members anchored within the case, a plurality of pairs of friction shoes each pair in frictional engagement with a corresponding one of said members, a plurality of spring followers each engaging a shoe cooperating with one friction member and a shoe cooperating with' the other friction member, a pair of spring elements in engagement with each` follower and a wedge engaging all of the shoes.

12. In a draft gear, a case, friction members anchored in the sides of the case, a plurality of pairs of friction shoes, each pair in frictional engagement with oppositely facing sides of a corresponding one of said members, a plurality of spring followers one engaging a plurality of said shoes and the other engaging others of said shoes, a pair of spring elements in engagement with each followerand a wedge engaging all of the shoes.

13. In a draft gear, a case, springs in said case and extending longitudinally thereof, friction members in separate zones of said case, each friction member being mounted in a space between different springs, friction shoes engaging the respective friction members, and wedging means cooperating with said shoes and resisted by said springs in compression of the gear, and an additional spring between said friction members and opposing movement of said wedging means.

14. In a draft gear, a case rectangular in cross section, springs in the respective corners of said case, a plurality of friction shoes one for each of said springs, a pair of friction members mounted in opposite walls of said case, opposite faces of one friction memberbeing engaged by a pair of said shoes and opposite faces of the other friction member Vbeing engaged by another pair of said shoes, and a wedge cooperating'with said 5* shoes to move the latter in frictional engagement with` said friction members and against the action of said springs, and another spring positioned centrally with respect to the first mentioned springs and between said 10 friction members vfor opposing movement of said wedge.

15.. In a friction draft gear a spring housing,` separate friction members anchored to opposite walls of said housing and extending 15 inwardly thereof, friction shoes on opposite sides of said friction members, a wedge for forcing said shoes inwardly into frictional engagement with opposite sides of each of said friction members, each'of said shoes 2O having a spring in alinement therewith for opposing movement thereof and a spring eX- tending between said friction elements and opposing movement of said wedge.

In testimony whereof, we have signed our 2'5 names to this specication this 10th day of November, 1928. f

ERNEST I-I. SCHMIDT.

HUBERT L. SPENCE. 

